This invention refers to a continuous gear change mechanism for thermal engine vehicles which can easily be adapted to suit farm vehicles, trucks, cars, etc.
The gear change mechanism detailed in this invention comprises separate input and output shafts onto which interlocking pinions and cogged wheels are mounted for interaction.
At present, gear change mechanisms used in all vehicles (industrial, trucks, cars, etc) are of the discontinuous type, i.e. they are restricted to use only under determined fixed transmision ratios, these are popularly known as "gears" in such a way that the vehicle speed in each one of them is proportional to the turning rate of the engine (r.p.m.) so when the speed needs to be increased once the engine runs at maximum turning rate allowed the only possible way is to select the next higher gear.
Gearboxes in use today are of two basic types: constant mesh and planetary gear.
The first type is more commonly used and consists basically of three main shafts (input, intermediate and output), with a pair of cogged wheels in gear with each other (constant mesh) locking the input and intermediate shafts and several couples of cogged wheels, as many as the number of gears, connecting the intermediate and output shafts.
Gear change mechanisms with planetary or epicycloidal gears are best suited to automatic gear boxes, whereby the gear changing operation is carried out automatically, i.e. without any action on the part of the driver; at any rate, these mechanisms turn out to be still discontinuous in power release.
Power transmission is completely mechanical in both cases, i.e. via interlocking cogged wheels with the appropriate interlocking device.
The Dutch manufacturer of D.A.F. vehicles has used a continuous gear change mechanism in medium size vehicles (car mod. DAF-44). This consisted of a special transmission belt between two pulleys which could vary their respective radii. This was achieved by the approach or the separation of the two tronconical plates that formed each pulley.
Attempts have been made to improve this type of device, but up to date a commercially feasible mechanism has not been yet manufactured, which is the main goal of this invention.
Continuous gear change mechanisms offer a clear improvement over discontinuous ones since they provide a better acceleration capacity, lower fuel consumption, lower pollution levels, longer useful life of the engine, etc.